A brake booster of this kind is known from DE 195 39 601 A1, for example, which is incorporated by reference. Said brake booster has what is referred to as external air routing. For this purpose, connecting conduits formed by a rib structure in a radially outer sealing bead of a first rolling diaphragm are formed between the working chambers in the region of the connection between the housing half shells.
DE 198 32 357 A1, which is incorporated by reference, has furthermore disclosed a brake booster in which the working chambers are connected by one or more connecting conduits designed as a cylindrical sleeve. For this purpose, the cylindrical sleeve penetrates the partition and the second movable wall and has a collar, by means of which it rests against a seal fitted into an opening in the partition. In this way, the first working chamber can participate in air admission when a control valve is opened.